It's easy to tell when a shop is deep into avionics wiring - at least it is in my shop! I generally start by hooking each wire up and one end and then estimating the length of each wire run. I then add about 10% to my guess, just to make sure that I won't come up short when attaching the second end to its destination - an inch too short is just aggravating. But that extra length always ends up somewhere, and that somewhere is the shop floor. Bits and pieces of wire, pitot/static tubing, masking tape (used to temporarily label wires) - and lots of pink or orange wire tires.
I like to lace all of my wiring bundles with lacing cord, but know that it is futile to do that until the very end, when all of the wires are in position. So I use cheap (Harbor Freight) tie-wraps to temporarily hold the bundles together. I use the brightly colored ones so that I know they are to be removed later - they are easy to spot that way, and easy to remove. After all of the wires have been run, I go through the entire wiring harness, lacing in permanent ties, and removing the colored temps - and that is how I make a nice looking avionics bay!
Meanwhile, the mess on the floor grows and grows - a sign of a busy shop!